Ukraine's president thanked the United States Saturday for its decision to provide lethal weapons to the country, while diplomats in Russia warned that the move would only cause more bloodshed.

The angry response from Moscow comes a day after the U.S. announced it will provide Ukraine with lethal weapons, in an effort to help the country with its fight against Russian-backed separatists in the eastern part of the country.

"Today, the United States clearly pushes [Ukrainian authorities] toward new bloodshed," Russian Deputy Foreign Minister Sergei Ryabkov said, adding that "American weapons can lead to new victims" in the neighboring country.

Kyiv, however, responded to the move with gratitude, thanking President Donald Trump for his "leadership" and insisting the weapons are not for offensive purposes.

"American weapons in the hands of Ukrainian soldiers are not for offensive [purposes], but for stronger rebuff of the aggressor, protection of Ukrainian soldiers and civilians, as well as for effective self-defense. It is also a trans-Atlantic vaccination against the Russian virus of aggression," Ukrainian President Petro Poroshenko said on Facebook in English.

The U.S. State Department said in a statement Friday that the decision to provide Ukraine with "enhanced defensive capabilities" is in keeping with the "effort to help Ukraine build its long-term defense capacity, to defend its sovereignty and territorial integrity."

The statement added that the "U.S. assistance is entirely defensive in nature."

An ABC-TV news report issued before the announcement said the "The total defense package of $47 million includes the sale of 210 anti-tank missiles and 35 launchers." The State Department did not confirm that those weapons would be among those supplied.

U.S. President Donald Trump has called for better relations with Moscow, but this deal would likely threaten that plan.

Earlier this month, U.S. Secretary of State Rex Tillerson warned Russia that the stand-off over Ukraine was the single most important obstacle to warmer ties between the two countries.